1. New Challenges in the European Area: Young Scientists 1 st International Baku Forum 2013| May 20 - 25, 2013 NANOWIRES IN SUSPENDED-CORE FIBER FOR NEW HIGH SENSITIVITY OPTICAL SENSORS Ricardo M. André randre@inescporto.pt Portugal

2. Contents Optical Fibers; Optical Fiber Sensors; Microstructured Optical Fibers; Suspended Core Fibers: – Tapering; – Setup; – Spectral Response; – Strain and Temperature Characterization; Conclusions. April 8th/9th, 2013Ricardo Melo André2/13

3. Different refractive índices in core and cladding; Propagation by total internal reflection. Optical Fiber n1n1 n2n2 n1n1 18 de Fevereiro de 2012Ricardo André - ENEF XII3/14

4. Optical Fiber Sensors How can we use Optical Fibers as sensors? Ricardo Melo André - IJUP 2010 - February 18 2010 4  L/L TT

5. Microstructured Optical Fibers (MOFs) Photonic Crystal Fibers (PCFs): – Index guiding PCFs – Photonic bandgap PCFs. Other MOFs: – Suspended Core Fibers, Bragg Fibers and others. Ricardo André - ENEF XII5/1418 de Fevereiro de 2012

6. Tapering of Suspended Core Fiber VYTRAN GPX-3000 – Tapering of microstructured optical fibers with extreme control; April 8th/9th, 2013Ricardo Melo André6/13

7. Tapers down to 20 μm of external diameter: – Nanocore diameter of 330 nm. No hole collapse; Cladding guidance below 600-700 nm core. Suspended Core Fiber Tapers 125 μm fiber2.1 μm core810 nm fiber April 8th/9th, 2013Ricardo Melo André7/13

8. Erbium-doped broadband source (1550 nm); Optical Spectrum Analyzer Ricardo Melo André Fiber Loop Mirror Setup April 8th/9th, 2013 3 dB coupler; Polarization controller; Suspended-core fiber section with taper. 8/13

9. Two interferometers: – High Birefringence; – Intermodal Interference; Higher visibility; Cleaner spectrum (only birefringence). Ricardo Melo André Spectral Response Analysis April 8th/9th, 20139/13

10. Strain sensitivity increase with taper waist diameter decrease. 2.1 μm core – 0.718 pm/με 810 nm core – 2.41 pm/με Ricardo Melo André Strain Characterization April 8th/9th, 201310/13

11. 2.1 μm core – 2.1 pm/K 810 nm core – 56.2 pm/K At lower diameters, higher birefringence dependence on temperature. Ricardo Melo André Temperature Characterization April 8th/9th, 201311/13

12. Conclusions Nanowire Characteristics: – High degree of protection / Independence of external medium; – Triangular, highly birefringent shape; – High temperature sensitivity; – Enhanced strain sensitivity; – High spectral stability; – Clean and easy-to-read spectrum; Ricardo Melo AndréApril 8th/9th, 201312/13

13. Acknowledgments COST TD1001 Information and Communication Technologies; Institute of Photonic Technology, Jena, Germany; Dr. Orlando Frazão and Prof. Manuel B. Marques; Thanks for your attention. Ricardo Melo AndréApril 8th/9th, 201313/13